A117874 Primes for which the level is equal to 5 in A117563.

17, 61, 131, 151, 271, 523, 541, 571, 751, 797, 971, 991, 997, 1291, 1321, 1361, 1741, 1901, 1913, 2011, 2179, 2297, 2341, 2441, 2447, 2551, 2791, 2851, 3301, 3511, 3761, 3803, 4051, 4391, 4397, 4423, 4441, 4561, 4651, 4703, 4759, 5101, 5471, 5483, 5521

Offset: 1

Author

Rémi Eismann, May 02 2006

Keywords

• nonn

Examples

			19=17+17 mod(3)=17+17 mod(15), level=5
157=151+151 mod(29)=151+151 mod(145) level=5
2203=2179+2179 mod(431)=2179+2179 mod(2155), level=5
		

Links

• Remi Eismann, Table of n, a(n) for n=1..10000

Crossrefs

Cf. A117078.

Programs

Mathematica

f[n_] := Block[{d, j = 2, p = Prime@n}, d = Prime[n + 1] - p; While[j < p && Mod[p, j] != d, j++ ]; If[j == p, 0, j]]; g[n_] := Block[{d, k = p = Prime@n}, d = Prime[n + 1] - p; While[k > 0 && Mod[p, k] != d, k-- ]; If[k == 0, 0, k]]; h[n_] := Block[{a = f@n, b = g@n}, If[a == 0, 0, b/a]]; Prime@Select[ Range@763, h@# == 5 &] (* Robert G. Wilson v *)

Extensions

More terms from Robert G. Wilson v, May 06 2006

Edited by N. J. A. Sloane, May 14 2006